Pressure comparison measurements between the CMI and the PTB in the range 0.07 MPa to 0.4 MPa

It was decided at the EURAMET TC-M meeting in Torino in 2006 to realize a comparison in gauge and absolute pressure up to 200 kPa as it would allow establishing a link to the CCM.P-K6 and CCM.P-K2 comparisons. This project from the beginning interested a lot of laboratories with participants, 22 of which have submitted results. The circulation of the transfer standard began on July 2009 and lasted until January 2012. No major problem occurred during the transport.The mesurand of the comparison is the effective area of a piston-cylinder determined in gauge and absolute pressure from 25 kPa to 200 kPa with pressure steps of 25 kPa. The transfer standard is a gas lubricated tungsten carbide piston-cylinder with an effective area of ~9.8 cm 2 , fabricated by DH Instruments and compatible with a PG-7601 pressure balance. Some participants used their own pressure balance while a pressure balance with a reference vacuum sensor has been circulated for the participants not equipped with this system.One participant (SMU, Slovakia) has never provided the measurement results and another participant (FORCE Technology, Denmark) submitted a revised set of measurement results after the pilot laboratory mentioned that the equivalence was not met.After the determination of the reference value, all the 22 participants who delivered the results in gauge pressure demonstrated equivalence respective to the reference value on most of the range. In absolute pressure the equivalence is demonstrated, for all nominal pressures, by all 17 participants who submitted results.

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“…It was equipped with 10 cm 2 piston-cylinder from DHI (serial number 248) with ceramic piston and tungsten-carbide cylinder. [12,13,14].…”

Section: 33mentioning

confidence: 99%

“…In a first time we calculated the weighted mean of the offset respective to the reference value of the CCM comparison: 12) where :…”

Section: Mathematics Used For Linking To the Ccm Comparisonsmentioning

confidence: 99%

Comparison in gas media (absolute and gauge mode)in the range from 25 kPa TO 200 kPa (EURAMET.M.P-K8)

et al. 2016

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“…They cover gauge and absolute pressures in the range from cca 10 kPa to 10 MPa, but with some modifications the instrument can also be used for negative gauge pressures [19,20]. This standard successfully participated in several comparisons registered within the key comparison data base, see [21][22][23][24][25][26]. Its most important part consists of three nominally 10 cm 2 PCAs made of tungstencarbide or hard ceramics.…”

Section: Introductionmentioning

confidence: 99%

Analytical solutions of some model cases of piston-cylinder assemblies

Pražák,

Hajduk,

Krajíček

et al. 2021

Meas. Sci. Technol.

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Pressure balances are an important part of the sets of primary pressure standards in many national metrology institutes. The most critical factor determining their accuracy is the effective area of their piston-cylinder assemblies (PCAs). This can be determined (for PCAs with undistorted pressure) by applying a numerical procedure based on a theory by Dadson while knowing a gapprofile (of an axisymmetric PCA approximation). The pressure balances are also a basis for the primary pressure scale of the Czech Metrology Institute. Hence, we wanted to test our programme by computing the effective area from the geometrical data. Therefore, we solved the analytical formulae of Dadson et al (1982) The Pressure Balance—Theory and Practice (London: Her Majesty’s Stationery Office) for several simple geometries with a constant gap width, which are easy to calculate analytically. It is shown that the analytical results always agreed perfectly with the results of our programme. This success confirmed the correctness of our programme. However, it also pointed out a problem of discretization which can be non-negligible, even in the case of relatively simple geometries. We assume that the analytical formulae obtained can be of practical use for any other pressure metrology laboratory requiring an independent way to confirm their own PCA-modelling software.

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“…Difference of each laboratory from the reference value at 800 kPa and 1000 kPaThe tables 4 to 6 show the equivalence of pairs of laboratories for the pressures 100 kPa, 600 kPa and 1 MPa. For each pair of laboratories, the tables give the observed relative difference D ij and the expanded uncertainty of the difference U ij (k=2) calculated as the quadratic combination of the two laboratories uncertainties and the uncertainty from the transfer standard stability 3. 47 * *…”

mentioning

confidence: 99%

Final report on key comparison EUROMET.M.P-K3.a in the gauge pressure range 50 kPa to 1000 kPa

et al. 2007

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The standards of 7 European Laboratories in the pressure range from 100 to 1000 kPa, with an option at 50 kPa, have been compared in the period 2000-2001. The transfer standard was a pressure balance equipped with a gas-lubricated piston-cylinder assembly of nominal effective area 980 mm². This assembly was formerly used as transfer standard for the key comparison CCM.P-K1.b. At the time of the comparison, the results relating to the effective area were not published. The link of the EUROMET.M.P-K3a comparison to CCM.P-K1.b will be established through the results of LNE, acting as the pilot laboratory. The comparison protocol for the EUROMET comparison was the same as for the CCM one. As the difference between the CCM reference value and the EUROMET reference value was not significant, the CCM reference value has been used to establish the equivalence statements of the participants to the EUROMET.M.P-K3a comparison to CCM.P-K1.b. The deviations from the reference value of all the laboratories but one are less than their estimated expanded uncertainty. Over 21 combinations of pairs of European laboratories, 18 demonstrate equivalence of the results at 1 MPa.

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Pressure comparison measurements between the CMI and the PTB in the range 0.07 MPa to 0.4 MPa

Cited by 5 publications

References 5 publications

Comparison in gas media (absolute and gauge mode)in the range from 25 kPa TO 200 kPa (EURAMET.M.P-K8)

Comparison in gas media (absolute and gauge mode)in the range from 25 kPa TO 200 kPa (EURAMET.M.P-K8)

Analytical solutions of some model cases of piston-cylinder assemblies

Final report on key comparison EUROMET.M.P-K3.a in the gauge pressure range 50 kPa to 1000 kPa

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